Abstract #2089

Physiological Noise Covariance Across Receiver Channels Explains Time-Series SNR Model for RF Coil Array FMRI Data

Jonathan R. Polimeni¹, Christina Triantafyllou¹,², Lawrence L. Wald¹,³

¹Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Harvard Medical School, Massachusetts General Hospital, Charlestown, MA, United States; ²A. A. Martinos Imaging Center, McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, United States; ³Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States

The original model for relating image SNR to temporal SNR demonstrated that physiological noise scales linearly with signal level, providing a quantitative relationship between image SNR and temporal SNR. Recently it has been demonstrated that fMRI data acquired with multi-channel array coils deviates from the standard model and the deviation appears to increase with element count. Here we consider the effects of physiological noise correlations across coil channels. Extending the physiological noise model to include a physiological covariance matrix can explain the observed deviation of the data from the Kruger model and provides an interpretation of the recently proposed models.